Current fire suppression systems employ either water, chemical agents, gaseous agents (such as "Halon", carbon dioxide, and heptafluoropropane) or a combination thereof. Virtually all of them are ozone depleting, toxic and environmentally unfriendly. This proposal employs a radically different approach. Specifically the use of high gas flux membranes to supply hypoxic breathable air for the prevention and suppression of fire. The high gas flow membranes provide compactness associated with desired portability on fire trucks in addition to low cost. The targeted hypoxic environment of 14-16% oxygen eliminates ignition and combustion of flammable materials while still being completely safe for human breathing. The high gas flow membranes convert air (21% oxygen) to hypoxic air (12-14% oxygen). By flooding the building with 12-14% oxygen one eliminates the concern for pockets of unbreathable air supply. Phase I will demonstrate the ability to rapidly and cost effectively supply this 12-14% oxygen and it's ability to rapidly reduce the room air to 14-16% oxygen. Tests will include first starting controlled fires and then demonstrating the systems ability to suppress the fire while maintaining oxygen levels at 14-16%. During the process, we will monitor for CO and other toxic gas formation. Parallel animal studies will validate the breath ability of the environment. We have strong relationships with major industrial membrane companies. These relationships enhance our ability to successfully commercialize these systems if this SBIR is shown to be successful.